Luminaires are expected to provide uniform lighting. This is desirable not only for the lighting of the respective surfaces, but also for the overall appearance of the luminaire.
This desire for uniform lighting in particular also relates to LED wall luminaires or LED ceiling luminaires. A problem with respect to any shadowing is the connection wiring which is frequently guided via the LEDs in the light path. This produces undesired shadows and artifacts for example on the luminaire cover.
In the case of typical LED luminaires, the connecting lines coming out of the wall and the lines that come from the light-emitting means are placed next to the light-emitting means so as to produce as little shadowing as possible. However, this negatively impacts the size of the light-emitting means and the shape of the luminaire. In addition, it is also not possible thereby to exclude that the connecting lines are imaged on the luminaire covers.
In practice, one solution which has also found widespread use is the placement of a separate ballast between the wall connecting line and the light-emitting means. The ballast requires space and either results in shadows on the luminaire cover or in dark spots due to a lack of lighting since the LEDs must be placed around the ballast. The consequence is a lower luminance in the region of the ballast, manifesting for example as a dark zone on the luminaire cover.